Emission of CO₂ from tropical riparian forest soil is controlled by soil temperature, soil water content and depth to water table

Goodrick, I., Connor, S., Bird, M.I., and Nelson, P.N. (2016) Emission of CO₂ from tropical riparian forest soil is controlled by soil temperature, soil water content and depth to water table. Soil Research, 54 (3). pp. 311-320.

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Abstract

Tropical forests play a key role in the global carbon cycle. However, little is known about carbon cycling in the substantial portion of tropical forests that are low-lying, with shallow and fluctuating water tables. This study aimed to determine what factors control emissions of CO₂ from soil in a riparian rainforest in Queensland, Australia. Emissions were measured over the course of 1 year, using static chambers. Emission rates were significantly related to soil temperature (0–0.1 m depth), soil water content (0–0.12 m depth) and depth to water table. The most efficient linear model of emissions as a function of measured parameters, which also included soil pH (0–0.1 m depth), had r² = 0.355. CO₂ emissions were highest (5.2–7.5 μmol m⁻² s⁻¹) at moderate soil temperature (24-28°C), water table depth (0.2–1.5 m) and soil water-filled porosity (0.25–0.79). They were lowest (<0.5 μmol m⁻² s⁻¹) at low soil temperature (<22°C) or when the water table was within 0.15 m of the surface. An additional interaction between temperature and soil water was determined in the laboratory. Incubation of soil cores showed that temperature sensitivity of the heterotrophic component of respiration increased as the soil dried. It is clear that models of soil respiration in lowland tropical forests should take into account depth to water table, which is a key, but hitherto unreported, controller of CO₂ emissions in tropical forests.

Item ID: 43675
Item Type: Article (Refereed Research - C1)
Keywords: carbon cycling, hydrology, soil respiration, tropical rainforest, soil moisture
ISSN: 1838-6768
Funders: Australian Research Council (ARC), Queensland Department of Environment and Resource Management (DERM)
Projects and Grants: ARC/DERM LP0669439
Date Deposited: 26 Jul 2016 02:10
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050102 Ecosystem Function @ 40%
06 BIOLOGICAL SCIENCES > 0699 Other Biological Sciences > 069902 Global Change Biology @ 30%
05 ENVIRONMENTAL SCIENCES > 0503 Soil Sciences > 050303 Soil Biology @ 30%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970105 Expanding Knowledge in the Environmental Sciences @ 40%
97 EXPANDING KNOWLEDGE > 970106 Expanding Knowledge in the Biological Sciences @ 40%
96 ENVIRONMENT > 9609 Land and Water Management > 960906 Forest and Woodlands Land Management @ 20%
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